- Father's Day is defined as a U.S. holiday on the third Sunday in June that is set aside to honor fathers.
A U.S. holiday in June meant to celebrate fathers is an example of Father's Day.
Father's Day definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
the third Sunday in June, a day set aside (in the U.S.) in honor of fathers
Father's Day definition by American Heritage Dictionary
The third Sunday in June, observed in the United States in honor of fathers.